Collapsible draw mandrel



y 1929- J. GROSSWEISCHEDE ET AL 1,713,962-

COLLAPSIBLE DRAW MANDREL Original Filed Jan. 24, 1927 5, ji'un fars:

.w-| 5 e M w (2-4 i Patented May 21, I 1929.

UNITED STATES PATENT OFFICE.

GERMANY,

STAHLWERKE .AKTIENGESELL- GERMANY, A CORPORATION OF GERMANY.

eoLLArsIBLn DRAW MANDREL.

Application filed January 24, 1927, Serial No. 163,133. Renewed larch 20, 1929.

This invention relates to an improved draw-mandrel of the collapsible type, for use in connection with a hot-drawing process, and which is illustrated on the accompanying drawing, in which Fig. 1 is a longitudinal section through the same, while Fig.

2 is a cross-section t-herethrough on the line- 2 of Fig, 1.

The improved collapsible draw-mandrel b, for drawing, a work-piece a, for instance a tubular body with closed end, through a die 0, consists of a wedge-shaped flat middle member d-taperedtoward its front end i and on both sides of which two lateral members e of about semicircular cross-section are located in contact therewlth and provided with elongated slots f in their wedge-shaped surfaces. which are in contact with the middle member d, into which slots engage proje'ctions g of said middle member in a slidable way so that the middle member can be displaced and brought outof contact with the two lateral members whereby the diameter or the circumference of the whole mandrcl can be reduced and thus the latter can be easily removed from the work-piece drawn.

What we claim, is

A collapsible draw-mandrel, comprising a longitudinal wedge-shaped flat middle member tapered toward its front end, two lateral members of about semicircular cross-section in contact therewith and having elongated slots in their contact surfaces, and projections on said middle member in slidable engagement with said slots.

In testimony whereof we have hereunto set our hands. 7

JULIUS GROSSWEISCHEDE. GEORG REICHENBECHER. 

